University of Wisconsin - Extension

One positive result of last December's record snowfall is that it may have kept your septic system from freezing.

"Bitter cold weather can mean costly problems in an important, although hardly cozy, part of your home -- your septic system," says University of Wisconsin-Extension water quality specialist Jim Peterson. "Septic systems are more likely to freeze up during extremely cold periods when there is little snow on the ground. This season's heavy snowfall acted as an insulator for the frost-prone earth above your septic tank and distribution system."

Septic distribution systems, networks of pipes through which sewage is carried from septic tanks to soil absorption fields, are especially vulnerable to freezing, Peterson adds.

"Because of this, the state has standards regarding the amount of ground cover for various septic systems," he says. "But because conditions vary across the state, you can have problems even if you follow those standards."

Insulating a septic system is one of many ways to reduce the chances of a freeze-up, he adds. Those who have had frequent problems in previous years might want to bury foam insulation above the septic system or add extra soil and sod at the surface. A thick layer of straw also can be spread above the system once the weather gets too cold to do any digging.

Once a septic system has frozen, there is typically only one way to thaw it. Steam out the system with the help of a trained professional.

Peterson emphasizes that a homeowner should never climb into a septic tank to unclog or defrost it. Septic tanks can lack oxygen or be full of toxic gases. A trained professional should be hired to do the job.

"Don't go into your septic tank for any reason," Peterson warns. "It's considered a confined space, so special equipment, procedures and supervision is required."

Homeowners can avoid potential problems by not packing down the insulating snow covering the septic system. Homeowners should not park or drive on snow covering a septic system, remove it for an ice rink or drive snowmobiles on it, says Peterson.

Several brochures on septic system management are available at local county UW-Extension offices.